Right. And I think a lot of the development with Steve in this movie is dealing with unwillingness to move on even after two years.

Exactly. There is a reason that, even after two years, Steve says that the reason he didn't go out on Saturday night was that his 'barbershop quartet' is dead. A part of him is still stuck in the past, and the movie seems to be about reconciling the two. There's no way they would have the movie begin with him getting closure. Audiences would probably feel cheated by "It's been two years, he's over it", and screenwriters would want a chance to portray his difficulties (though I doubt it will be him crying and staring at old photos-that's reserved for Bucky ).

I do think that they could have introduced Sharon in a bigger role, though. However, they would have had to keep the relationship platonic for this movie, and probably not reveal her surname till the end. Otherwise, it would seem like Sharon was Peggy's 'replacement', which would be bad for everyone involved. But yeah, I would have been into him partnering with the mysterious Agent 13.